Harman Kardon A500 questions

Jenkster

Jenkster

Bonzo!
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I just picked up a very nice HK A500 from a fellow AK'er. It is in very, very nice cosmetic condition. Sonically, it has a bit of a hum and crackle. It appears to be stock so I assume I should start with the filter caps and maybe power supply caps? Going to test the tubes tomorrow. Power tubes are labeled Harman Kardon, the 4 12AX7's and the 12AU7 are Telefunkens. I posted a want for an owners manual in Digital Docs but, if anybody has one, I would love a copy. Thanks!

Here's some pics.
 
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Power supply/filter caps and coupling caps are must-replace items on these.

That's usually, besides making sure you have a set of all-good tubes, all you have to do to them. They usually perk right up and sound excellent, with that being done.

Regards,
Gordon.
 
GordonW said:
Power supply/filter caps and coupling caps are must-replace items on these.

That's usually, besides making sure you have a set of all-good tubes, all you have to do to them. They usually perk right up and sound excellent, with that being done.

Regards,
Gordon.
Click to expand...

Thanks Gordon, it looks like the caps are all pretty straight forward save for the the 400/50 cap in the C3 can? It is real clean underneath. I have high hopes for this amp and my Klipsch Forte's.:yes:
 
That's a sweet looking amp - good luck:thmbsp:!

By the way I had Jim McShane put a parts list together for me - I'll email it to you - it's basically everything you need (resisitors, caps and diodes) for a full restore.

Jim has a pretty good reputation for using the very best parts and he knows a thing or two about Harman Kardon's.

I bought the parts from him but have yet to restore my A500 (got sidetracked by a Fisher 800C project).
 
visman said:
That's a sweet looking amp - good luck:thmbsp:!

By the way I had Jim McShane put a parts list together for me - I'll email it to you - it's basically everything you need (resisitors, caps and diodes) for a full restore.

Jim has a pretty good reputation for using the very best parts and he knows a thing or two about Harman Kardon's.

I bought the parts from him but have yet to restore my A500 (got sidetracked by a Fisher 800C project).
Click to expand...

Hey, thanks for the info, visman, I appreciate it! Thanks also for the download on the OM.:thmbsp: I would also like the parts list, will definately save me some time. Are you going to use new cans or go the "under the hood" route? I guess it's fasionable to re-stuff the existing cans as well. I really look forward to getting it all fixed up.
 
visman said:
That's a sweet looking amp - good luck:thmbsp:!

By the way I had Jim McShane put a parts list together for me - I'll email it to you - it's basically everything you need (resisitors, caps and diodes) for a full restore.

Jim has a pretty good reputation for using the very best parts and he knows a thing or two about Harman Kardon's.

I bought the parts from him but have yet to restore my A500 (got sidetracked by a Fisher 800C project).
Click to expand...

Mine was the first A500 Jim restored and he did a fantastic job on it. He did make one little mistake though. When he replaced the RCA inputs and outputs, he put the red on channel A which it usually the right channel, but not on these amps. Channel A is left and channel B is right. I've since changed all but one of them. I forgave him, it was an honest mistake. :D

Yours sure looks like a clean one. You're going to enjoy it for sure!

BTW...for anyone planning on replacing their old RCA jacks, any of the dual RCA jacks designed as replacements for a Dynaco ST70 are drop in replacements for the two sets of two for the tape mon and tape out on the A500.

A500b.jpg
 
EVGuy said:
Mine was the first A500 Jim restored and he did a fantastic job on it. He did make one little mistake though. When he replaced the RCA inputs and outputs, he put the red on channel A which it usually the right channel, but not on these amps. Channel A is left and channel B is right. I've since changed all but one of them. I forgave him, it was an honest mistake. :D

Yours sure looks like a clean one. You're going to enjoy it for sure!

BTW...for anyone planning on replacing their old RCA jacks, any of the dual RCA jacks designed as replacements for a Dynaco ST70 are drop in replacements for the two sets of two for the tape mon and tape out on the A500.

A500b.jpg
Click to expand...

Great looking amp and some nice work!:thmbsp: I don't think I will replace the RCA jacks, they appear to be fine. I think I am going to take a minimalist approach at first and go from there. Here's some pics "under the hood" and the back side. It looks pretty stock to me.:yes:
 
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I don't think I've seen another like yours with the output transformers mounted on their ends like that.
 
EVGuy said:
I don't think I've seen another like yours with the output transformers mounted on their ends like that.
Click to expand...

Wow, now that you mention it, that is a bit odd.:scratch2: I wonder if they are replacemtents or a factory anomaly or??? Maybe this was a kit that was not built correctly? I did find out the power tubes are a bit long in the tooth. The Telefunken 12AX7's and 12AU7 test at above 95%.
 
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Looks like the OPT's might be lifted from the HK TA5000X receiver, which was essentially an A500 amp with a AM/FM tuner all on the same chassis, they look like those-end mounted, one of the transformer ID numbers used in the TA5000X is FT 4725698 (they may have used others as well). I did have one A500 with the transformers like that, I expect it was factory built (it was not a kit), and they probably were used as a factory substitute. Might check your serial number, mine was 7342254, there may have been a time when the ran a batch this way.
 

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buickguy62 said:
Looks like the OPT's might be lifted from the HK TA5000X receiver, which was essentially an A500 amp with a AM/FM tuner all on the same chassis, they look like those-end mounted, one of the transformer ID numbers used in the TA5000X is FT 4725698 (they may have used others as well). I did have one A500 with the transformers like that, I expect it was factory built (it was not a kit), and they probably were used as a factory substitute. Might check your serial number, mine was 7342254, there may have been a time when the ran a batch this way.
Click to expand...

Thanks man, I do know that back in the day everything didn't have to be exactly the same as the next one. That does make sense as I am sure this was factory made and certainly appears to be original.:yes:
 
Hi Everyone,
I just acquired an H/K A50k from original owner, I was lucky enough to get the original plastic cover over the face of amp (its never been off!), original box (box is rough and the original receipt)
I would like to have the original manual and wiring diagram if possible. I tried several links on here but none of them work.

Thanks in advance if anyone could help!
 
Mazdatech said:
Hi Everyone,
I just acquired an H/K A50k from original owner, I was lucky enough to get the original plastic cover over the face of amp (its never been off!), original box (box is rough and the original receipt)
I would like to have the original manual and wiring diagram if possible. I tried several links on here but none of them work.

Thanks in advance if anyone could help!
Click to expand...

You'll find at least the schematic for the A500 here: http://shermanr.web.prw.net/Page_02.htm
 
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